japanese folklore
tengu, oni, kappa, etc.

very nice

Ninja would be considered as youkai too?

This is actually a pretty comical take on Muramasa: The Demon Blades.

Not sure I trust that shaved ice . . . not because of the yuki-onna, I know she'll have made it with loving care. No, it's because of Mr. God of Pestilence sitting on her stall's roof that I doubt the safety of it.